This invention relates to the joining or stitching of limp fabric or material to form useful articles. In particular, the invention relates to apparatus useful in automated or computer-controlled sewing of fabric.
Classic assembly line manufacture of articles constructed of limp fabric consists of a series of manual operator-controlled assembly stations. One drawback of this classic fabrication technique is that it is labor intensive; that is, a large portion of the cost of manufacture is spent on labor. To reduce costs, automated or computer-controlled manufacturing techniques have been attempted. One such method is disclosed in U.S. application Ser. No. 231,381, previously incorporated herein by reference.
In general, automated manufacturing techniques for limp fabric are limited to problems caused by inaccurate joining of the fabric at the seams. This problem can be traced to the failure of most automated systems to have sufficient control of the fabric near the needle or joining head. In manual operator-controlled assembly, the proper fabric control is achieved by pressure of the operator's fingers or, in certain limited instances, a jig specific edge reference local aligner mechanism has been utilized to supply the proper pressure. To date, the mechanical devices such as the local aligner mechanism have not been sufficiently adaptable for use by automated systems in forming complex joining patterns.